/Engine/Source/Runtime/MovieScene/Public/Channels/MovieSceneDoubleChannel.h
int32 AddCubicKey ( [FFrameNumber](API\Runtime\Core\Misc\FFrameNumber) InTime, double InValue, ERichCurveTangentMode TangentMode, const [FMovieSceneTangentData](API\Runtime\MovieScene\Channels\FMovieSceneTangentData) & Tangent )